HIREN

INSERT TRANSFOREMR DATA

RATING 35 ( MVA )

PRI. VOLTAGE 33 ( KV )

SEC. VOLTAGE 11 ( KV )

% IMPEDANCE 10 ( % )

PRI. CURRENT 612.34119 ( AMP )

SEC. CURRENT 1837.0236 ( AMP )

FAULT CURRENT 18.370236 ( KA )

INSERT REQUIRED CT DETAILS

CT1 PRI 650 ( AMP )

CT1 SEC. 1 ( AMP )

i1 0.9420634 ( AMP )

CT2 PRI 2000 ( AMP )

CT2 SEC. 1 ( AMP )

i2 0.9185118 ( AMP )

ICT REQUIRED FOR THE SCHEME

ICT(D-Y) 1/ 0.5921541 ( AMP )

ICT(D-D) 1/ 1.025641 ( AMP )

ICT(Y-D) 1/ 0.5629165 ( AMP )

ICT(Y-Y) 1/ 0.5921541 ( AMP )

NOTE : 1 - For the connection D-D at primary side ICT=1/1 assumed.

2- For the connection Y-Y at primary side ICT=1/ 0.577 assumed.

3 - Star side CT is DELTA connected and delta side CT is STAR connected.

4 - For differential shemes testing you have to short all three phase for INZONE & OUT ZONE ( THROUGHFAULT ) condition.

DIFFERENTIAL SCHEME TESTING

APPLIED VOLTAGE 500 (VOLT)

(D-Y) (Y-D) (Y-Y) (D-D)

i1 0.142737 0.139168 0.142737 0.142737 (AMP)

i2 0.142737 0.139168 0.142737 0.142737 (AMP)

PRI 92.77897 SEC 278.3369 (AMP)

IN 0 0 0 0 (AMP)

OUT 0.142737 0.139168 0.142737 0.142737 (AMP)

4 - For differential shemes testing you have to short all three phase for INZONE & OUT ZONE ( THROUGHFAULT ) condition.

HIREN Calculation of VK & R-Stab Reqd for Generator Differential ( High Inpidance ) protection.

ENTER THE GENERATOR DETAILS IF ONLY KVA DETAILS IS GIVEN ENTER DETAILS OF CT VK GENERATED BY 5P CT

KW 12000 KVA 15000 CT Pri. 1000

Voltage 11000 Volts 11000 CT Sec. 1

P.F 0.8 xd" 0.18 CT resi. 6

xd" 0.18 KW 12000 2RL 1

KVA 15000

Full Load Current 787.2958 Amp 787.2958 Amp

20% OL for CT 944.755 Amp 944.755 Amp

Fault Current 4373.866 Amp 4373.866 Amp

Fault Current Given 5000 Amp 9270 Amp

CT O/P 5 Amp 9.27 Amp

10% Error 5.5 Amp 10.197 Amp

VK Required 77 Volts 142.758 Volts

Reqd PS of Relay 0.1 Amp 0.1 Amp

VA at Reqd PS 1 VA 1 VA

Relay Resistance 100 Ohm 100 Ohm

R-Stab Reqd. 250 Ohm 548.9 Ohm

Reqd Watts 23.716 Watts 37.12852 Watts

V Peak 59.89194 Volts 20586.75 Volts

Calculation of VK & R-Stab Reqd for Generator Differential ( High Inpidance ) protection.

ENTER THE GENERATOR DETAILS IF ONLY KVA DETAILS IS GIVEN ENTER DETAILS OF CT VK GENERATED BY 5P CT

Amp CT sec. 1 Amp

Amp CT resi. 6 Ohm

Amp VA Given 20 VA

Ohm ALF Given 20

VK 520 Volts

HIREN

TMS Settings as per required tripping time. Calculate Required TRIPPING TIME

Required Tripping time 19 Sec Set Current at Relay

Expected Fault current at Sec. 1.2 Amp Multiflying factor for current

Set Current at Relay 1 PS Current at relay Terminal

TMS setting

For NINV curve, 3 Sec

For NINV curve, 3 Sec

Set TMS tI> : 0.495776 0.5

Trip Time

For VINV curve,

For VINV curve,

Set TMS tI> : 0.281481 0.28

Trip Time

For EINV curve,

For EINV curve,

Set TMS tI> : 0.1045 0.1

Trip Time

For LINV curve,

For LINV curve,

Set TMS tI> : 0.031667 0.03

Trip Time

For RI Curve-O/C-ABB

Trip Time

For RD Curve-E/F-ABB

Trip Time

According to the standard BS 142: 1966 the effective

current range is defined as 2...20 times the set start

current. If the time/current characteristic is normal

inverse, very inverse or extremely inverse, the function

has to start at the latest when the current exceeds the

set start current by 1.3 times. For the long-time inverse

characteristic, the effective current range is specified to

be 2...7 times the set start current and the relay is to

start at the latest when the current exceeds the setting

value by 1.1 times.

Calculate Required TRIPPING TIME

1 Amp

1.2

1.2 Amp

0.5

19.16187 Sec

33.75 Sec

90.90909 Sec

300 Sec

4.045307 Sec

3.895836 Sec

IEEE 80

The Cross Section area required for Thermal Withstand capability is given by the formula

Equivalent Short Circuit Current ISC 40 kAShort Circuit Duration T 3 Second

Max. Permissible Temp. During short circuit θ 215 0 C

0.622960258

148175.8926

Area of Cross Section required A 384.9362 Sq. mm

The Cross Section area required for Thermal Withstand capability is given by the formula

`

SET CURRENT AT RELAY MEANS STARTING CURRENT

EXPECTED FAULT CURRENT IS IN TIMES OF SET CURRENT

MULTIPLYING FACTOR MEANS IN TIMES OF SET CURRENT